Many industrial processes, particularly metal refining, involve feeding particulate solid reagents into bodies of liquid. A notable example is the addition of carbonaceous material, and the addition of lime and/or other slagging agents, into molten metal in an electric arc furnace (EAF), in which there is usually a molten slag phase atop a molten metal phase. The present invention provides advantageous apparatus and methodology useful for carrying out this sort of activity.
In EAF operations, carbon is injected to react with molten slag to decrease iron oxides (by reduction of the iron oxides to metallic iron) and to optimize foamy slag practice. This practice results in reduced electrode consumption, reduction in arc noise, increased lining refractory lifetime, and overall improved power economy and specific thermal efficiency. Carbon injected through the slag layer can intentionally raise carbon levels in the molten metal when desired.
In EAF operations, lime can be injected through sidewall injectors to improve slag practices through better slag chemistry control. This practice can result in a cleaner environment for the shop (less dust losses from the furnace) and reduced losses of lime to the furnace evacuation system, lowering the specific lime consumption, reduced maintenance cost compared to mechanical systems, faster dissolution of lime related to increased surface area, and overall improved steel process performance. Lime injection also participates in sulfur and phosphorus removal.